Telephone and the like



May 14, 1929. H. J. ROUND TELEPHONE AND THE LIKE Filed Nov. 11, 1924 INVENTOR HENRY JOSEPH ROUND TORNEY Patented May 14, 1929.

STATES.

HENRY JOSEPH ROUNJD, F LONDON, ENGLAND, ASSIGNOR TO RADIO CORPORATION 0F AMFRICIA, A. CORPORATION OF DELAWARE.

TELEPHONE AND THE LIKE.

Application filed November ll, 19%, derial No. 749,118, and in Great Britain November 29, 1923.

This invention relates to telephones and the like and its primary object is to provide an improved loud speaker.

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According to this invention ll secure to the edge of a stiff diaphragm a coil which is im mersed in a magnetic field so that when speech currents or the like pass through the coil it is moved and consequently the diaphragm is also moved.

Preferably the diaphragm is provided with a cylindrical flange on which the coil is mounted and this flange extends into the annular air gap of a. magnet constructed in the term of a torus and containing within it a magnetizing winding.

The invention is illustrated by the accompanying drawing, in which the four figures are sections through four different moditications.

lln Figure 1 A is a stiff diaphragm around the edge of which is a cylindrical flange B on which is mounted a coil 0. The diaphragm is supported by a thin rubber ring D in such a posit-ion that the coil C is suspended in the annular air gap of a magnet E in the form of a torus, containing within it a ma netizin windin not shown.

b b b It will be understood that when speech or like currents are passed through the coil, the diaphragm will be moved as a whole and will produce sound waves, and that when sound waves fall upon the diaphragm they will move it and therefore corresponding currents will be produced in the coil.

Figure 2 shows a similar arrangement, but the diaphragm consists of a double cone having still ribs F inside it.

lln Figure 3 the magnet is so modified in shape that it can support a horn Gr across the entrance'of which the diaphragm extends.

Figure 4 shows an arrangement in which the horn is mounted on the same side of the magnet as is the diaphragm, this arrangement being suitable for smaller diaphragms than is that of Figure 3.

The diaphragm is preferably formed of some such material as ebonite, celluloid or paper treated with a phenol condensation product, and may be given any natural period by means of the rubber support. In some cases, however, in place of supporting the diaphragm by a rubber ring as shown, I may support it by radial wires covered wholly or partly with some sealing material such as rubber or oiled silk. Or again, a thin flexible metal ring can be employed to support the diaphragm.

Having now particularly described and as-' certained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is 1. In a loud speaker a diaphragm having truss members, and an operating coil at tached at its edge.

2. in a loud speaker a diaphragm having truss members, and an operating coil attached at its periphery, the coil being afl'ected by a constant magnetic field.

3. Aloud speaker comprising a supporting member, flexible supporting means attached thereto, a vibratile diaphragm attached to the free edge of the supporting means, said diaphragm being conical and relatively large whereby the use of a horn is avoided, a perpendicular flange attached to the junction of the diaphragm and the supporting means, and an operating coil associated with the flange.

4. A loud speaker comprising a supporting member, flexible supporting means attached thereto, a vibratile conical diaphragm attached to the free edge of the supporting means, a perpendicular flange attached to the junction of the diaphragm and the supporting means, an operating coil associated with the flange, and means for producing a continuous flow of flux at right angles to the direction of the winding, said diaphragm be ing conical and relatively large whereby the use of a horn is avoided.

5. In a loud speaker a double. cone dia phragm, strut members associated with the diaphragm, and flexible supporting means at the periphery of the diaphragm mounted in an opening of a mounting member.

6. In combination, a magnetic field having an air gap in a circular form, a conducting winding supported in the air gap by means of a flexible mounting, and a double cone diaphragm attached at its periphery to the winding, the whole being supported by means of a mounting member.

7. In a loud speaker a diaphragm having two cone type elements associated together by means of braces, a supporting member, supporting means comprising a flexible strip attached at one edge to the diaphragm and at the other edge to said supporting mem bet, and operating means attached to the diaphragm at the junction-between the flexible supporting means and the diaphragm.

8. A piston type diaphragm composed of two cone type elements joinedtogether at the periphery and braced against each other by means of strut members, a supporting member, a flexible supporting member mounted in said supporting'member, and an operating flange connected to said elements at the junction of the flexible supporting member, said flange bein immersed in a magnetic field. 9. A loud speaker comprising a supporting memberya conical shaped diaphragm, re-

'- 'silie'nt' supporting means between the edge of said diaphragm and said supporting member and a driving means connected to said diaphragm around its edge, said diaphragm being relatively large an having its outer field.

HENRY JOSEPH ROUND. 

